1. Field of the Invention
The present invention relates to a copying machine paper supply system comprising a paper supply cassette provided with a plate for supporting copying papers and a pushing-up apparatus for pushing up the plate to urge the copying papers thereon upwardly, a space for housing the paper supply cassette therein and a cassette holding member installed in the space for enabling insertion and removal of the paper supply cassette, and to a paper supply cassette used in such a copying machine.
2. Description of the Prior Art
At present, copying machines using paper supply cassettes are popular. However, there are generally paper supply cassettes of small volume type housing about 250 pieces of copying paper therein and paper supply cassettes of large volume type housing about 500 pieces of copying paper therein. Copying paper sheets of B5 size and A4 size provided in JIS, which are used frequently, should be housed in a paper supply cassette of large capacity to reduce the number of cassette supply operations. On the contrary, copying paper sheets of B4 size and the like, which are large-sized and used at lower frequencies, should be housed in a paper supply cassette of smaller capacity, since such paper supply cassette otherwise would be relatively heavy, thereby resulting in the disadvantages of difficulty of handling and the possibility that the copying papers become deteriorated by moisture and the like. In addition, at present paper supply cassettes of small volume type housing about 250 pieces of copying paper and those of large volume type housing about 500 pieces of copying paper are used since copying papers are frequently packaged with 500 pieces as a unit.
"Single cassette type" copying machines, which accommodate only one paper supply cassette, and "plural cassette type" copying machines, which accommodate a plurality of paper supply cassettes, are on the market. However, in consideration of the above described present state of copying machines, "single cassette type" copying machines are constructed to house only a paper supply cassette of small volume type or only a paper supply cassette of large volume type. That is to say, a paper supply cassette housing 500 pieces of copying paper cannot be employed in "single cassette type" copying machines in which a paper supply cassette housing 250 pieces of copying paper is exclusively employed, and a paper supply cassette housing 250 pieces of copying paper cannot be employed in "single cassette type" copying machines in which a paper supply cassette housing 500 pieces of copying paper is exclusively employed. Although a "plural cassette type" copying machine is provided with a space for housing a paper supply cassette of small volume type therein and a space for housing a paper supply cassette of large volume type therein, such a machine has the disadvantage that only a paper supply cassette of small volume type can be positioned in the space for housing paper supply cassettes of small volume type, and only a paper supply cassette of large volume type can be positioned in the space for housing paper supply cassettes of large volume. In such arrangement, a cassette-holding member extends across substantially the entire width of the space for housing the paper supply cassette, and the bottom surface of the cassette is supported over the entire width thereof.